FolderIt is possible to categorize RSS feeds to folders and read all entries of a folder. This is very useful to read one category --- "XOOPS Cube". GIJOE's, ryuji's, tohokuaiki's and other writer's updates are collected to one view.
Star & TagMost of blogs I'm subscribing are written in English. But, because I am not good at English, I can't read an interesting entry quickly. Star & Tag are useful. I add Star or Tag to an interesting entry. By that, the entry is categorized to the special folder. So I can translate them later. Tag is not temporary stock, but permanent memorandum.
In Japan, Livedoor RSS Reader service is popular. But, I don't use it, because the view screen of this service is narrow and it doesn't have the same folder function as Google Reader. In addition, Livedoor RSS Reader doesn't match the mood of English Blogs, because it displays Japanese character.
However, Livedoor Reader may have been improved until now. Because I don't use Livedoor Reader since the first impression, I don't know the recent version of the reader.